非线性形变现象在指纹图像中十分普遍，严重地制约了指纹识别系统的识别性能。为了克服指纹图像中的全局非线性形变，本文提出了指纹图像匹配“整体对齐，局部匹配；粗糙对齐，精确匹配”的原则。在此基础上，本文设计了一种细节点局部邻域描述子，利用该描述子对齐指纹图像,研究了基于该描述子的指纹图像相似度计算方法。基于FVC 2000 DB2、 FVC2002 DB1和FVC 2004 DB2的一系列实验结果表明，本文提出的算法性能优于同类算法，能够有效抑制非线性形变对指纹图像匹配的影响。

Nonlinear distortion is common in fingerprint images. It degrades the performance of fingerprint verification systems severely. To overcome the global distortion problem in fingerprint images, this paper presents a principle for distorted fingerprint image matching as “align globally while match locally, align coarsely while match accurately”. Based on such a principle, this paper defines a local minutia descriptor, and further uses it to align and match two fingerprint images. The similarity computing method is especially studied. Experimental results on FVC 2000 DB2, FVC2002 DB1 and FVC 2004 DB2 prove the superiority of the proposed method. It can restrict the effect of nonlinear distortion on fingerprint image matching.